article from the LA Times, it appears Clooney was under a lot of pressure to make the film by the deadline, and that seemed impossible.
Way back in July, when GoldDerby released a claim that The Monuments Men would gun for below-the-line categories due to the film being 'popcorn fare'. Visual Effects was one of them, before the theory was debunked. It is now fully possible that it was Clooney's intention to make a good film instead of what appeared to be Oscar bait. It's a smart move by Clooney, especially since the film was caught in the middle of a jam packed year. I mean, if filming concludes in July, you can't expect to get the desired film without more time.